Trends in Micronutrient Laboratory Testing in Switzerland: A 7-Year Retrospective Analysis of Healthcare Claims Data

Background: Micronutrient laboratory tests (MLT) are increasing in many healthcare systems. This study assessed time trends of annual MLT incidence in the Swiss population and examined the frequency of specific MLT, defined as the number of yearly tests performed in individual persons. Methods: For annual time trends, we used a longitudinal design with a seven-year observation period (2012-2018) and for yearly testing frequency we used a cross-sectional design (2018 only). The database consisted of nationwide insurance claims from adult persons. Results: Persons with MLT compared to persons without were older (mean age 57.1 years vs 48.6 years) and to a higher proportion female (65.1% vs 45.5%). Between 2012 and 2018, we included 6.7 million person years and found an increase in the proportion of persons receiving any MLT from 24.5% to 35.0%. Tests with strongest absolute increase during the observation period were vitamin D (from 7.4% of persons to 20.4%), vitamin B12 (from 9.0% to 17.6%) and ferritin (from 17.4% to 26.6%). In 2018, vitamin D and vitamin B12 tests were performed more than once in 4.5% and 3.3% of the population, respectively. Conclusion: We found that the Swiss population undergoes MLT with high and increasing frequency. Testing for vitamin D, vitamin B12 and ferritin is very common and of questionable appropriateness.